The increasing spread of small and medium sized energy generation units, which are somewhere connected to an AC power grid, increasingly complicates the operation control of AC power grids. In case of an increasing global demand of electric power in an AC power grid, the power of a central power plant may simply be increased, without considering particular characteristics of a topology of the AC power grid, i.e. connections of the various grid levels, subdivisions of a grid level into individual branches or electric relative positions of energy consumption and/or energy generation units with regard to each other. However, this does not apply to local energy generation units or systems of a plurality of energy generation units. Here, problems with regard to distributing the power in the AC power grid may occur due to local imbalances between generation and consumption of electric power. For example, there may already be a local surplus of electric power due to local energy generation units, even if the overall demand in the AC power grid exceeds the overall supply of electric power. A further increase of the energy fed by these local energy generation units then results in at least locally leaving the allowable operation range of the AC power grid in that, for example, voltage threshold values are exceeded and/or operation equipment, particularly electric lines, is overloaded. Similarly, under these circumstances, it is of little use to switch off an energy consumption unit in an area of the AC power grid in which the surplus of electric power is present, in order to reduce an overall lack of electric power. Particularly, a operation control of an AC power grid by means of global control signals directed to all connected controllable energy generation units and energy consumption units in a same way is not suited for solving this contradiction between local and global problems.
DE 10 2010 006 142 A1 discloses an energy portal for controlling an energy supply by an energy generation grid. In controlling operation parameters of the energy generation grid the energy portal considers feed-in factors, energy generation grid measurement values and prognosis information. The energy portal includes a feed-in factor receiver for receiving feed-in factors which may be pre-set by an operator of an energy distribution grid, an energy generation measurement value receiver for receiving measurement values of the energy generation grid, a prognosis information receiver for receiving prognosis information, an evaluation unit for evaluating the measurement value, feed-in factors and prognosis information, and an operation parameter controller controlling the operation parameters of the energy generation grid based on the evaluated measurement values, feed-in factors and prognosis information using the feed-in factors as a control variable. In this way, it shall be achieved that the feed-in factors pre-set by the operator of the energy distribution grid are met. Actually, however, this result may only be achieved when exactly knowing the topology of the entire AC power grid.
DE 10 2007 055 517 A1 discloses a method of operating an energy supply grid. The energy supply grid includes at least one or a plurality of energy generation units and/or one or a plurality of energy consumption units, wherein one or more supply categories having a pre-set priority is/are assigned to each of them. Based on the supply classes, the energy generation units are computer-controlled with regard to the energy supplied, and/or the energy consumption units are computer-controlled with regard to the energy consumed. In the course of the known method, a computer-based determination of the topology of the energy supply grid shall take place to enable a demand-based control of the respective units of the energy supply grid. Topology data of an energy supply area shall represent the structure of the grid of the supply lines and statistical machine data of the units in the respective energy supply area. The structure of the line grid shall be automatically recognized by exchange of data between the respective power distribution computer and an area computer. The area computer shall periodically download the equipment values to update the topology data for the energy supply area. Particularly, a power distribution computer, when connected to a supply line, shall automatically determine which units are already connected to the respective supply line. For this purpose, the power distribution computer measures physical line data, like for example the impedance. Afterwards, the information obtained by the power distribution computer are transferred to the area computer of the respective energy supply area. The area computer uses this data for determining a topology of the energy supply area. These measurements, however, are not sufficient to determine a topology of a grid section at a precision sufficient for an optimized operation control within the grid section.
DE 10 2008 057 563 A1 discloses a method and an apparatus for grid conforming operation of a low voltage grid comprising a plurality of local energy generation units and/or energy consumption units. The units are connected to a superordinate facility common to all units, which is operated by an energy trader, for exchanging information via a communication medium. Each unit comprises an energy manager which, by means of an optimization program and a fixed tariff profile, calculates an economically optimized operation plan for its energy consumption units and generators. A grid conforming operation is achieved in that grid parameters resulting at grid connection points of the units are surveyed for keeping tolerance ranges assigned to them, and in that the superordinate facility, when the grid parameters at at least one grid connection point leave the assigned tolerance range, transfers an amended tariff profile to at least one critical unit to bring the grid parameters at least closer to the tolerance ranges again. If, by means of this known method, the operation control of a grid section shall be optimized, all units consuming or generating relevant amounts of energy have to be connected to the facility operated by the energy dealer. Further, the indirect control of the units via the tariff profiles transmitted to them is slow.
EP 2 012 132 A1 discloses a consumption and status meter which comprises an analyzer for power consumers. Individual consumers are recognized by a finger print of their power consumption. If the power consumption is determined at different sockets, it is also recognized to which socket the respective power consumer is connected.
There still is a need of a method of determining the topology of a grid section of an AC power grid, which provides sufficient information as to an, at first, unknown topology of a grid section to optimize the management of the AC power grid in the grid section by means of energy consumption and/or generation units which are controllable with regard to their connection power values.